Percutaneous transhepatic cholangiogram and biliary drainage (PTCB) is procedure performed by an interventional radiologist, a medical doctor having specialty training in diagnostic radiology and subspecialty training in interventional radiology. This procedure involves placement of a needle followed by a wire and a catheter through the skin of the right flank after local anesthesia and sedation have been administered. This procedure is performed using sterile technique in a catherization laboratory in a hospital, using C-arm fluoroscopic (X-ray) guidance. The procedure allows the physician to look at the bile ducts and to bypass any obstructions of flow (biliary drainage) of bile from the liver into the small bowel where bile aids in the digestion of fatty foods.
Percutaneous biliary drainage (PBD) is a well described intervention used both as a temporizing procedure and as definitive therapy in patients with obstructive jaundice. Because these are invasive procedures, however, complications can occur. Complications commonly associated with PBD include cholangitis (13%-47%), fever secondary to bacteremia (11.2%), sepsis (3.9%-8.0%), hemobilia (3.5%-9.6%), pancreatitis (0%-10%), biloma formation (1%-3%), bile hypersecretion with electrolyte imbalance (5%), and death (0.6%-5.6%).
A previously unreported complication of PBD, brachial plexus neuropathy, has occurred twice during our last 617 cases, for an overall rate of 0.32%. Moreover, a single case of brachial plexus neuropathy has recently occurred in a patient undergoing a right heart catheterization in our lab.
The details of our aforementioned cases are reported herein below.
Case 1: A 58 year old female with a small pancreatic carcinoma and a nondilated biliary system was admitted to the department for preoperative placement of a PBD catheter. The stent was to be used as an aid during surgical reconstruction. The patient was placed on the table in a supine position with her right hand under her head and right arm in an abducted position, leaving the right lateral flank exposed for procedural access. Despite innumerable passes with a 22 gauge Chiba (Cook, Bloomington, Ind.) needle the nondilated biliary tract could not be pacified. The procedure was terminated after a time of approximately two hours. Nine mg midazolam hydrochloride and 450 ug fentanyl citrate was utilized for conscious sedation during the case. She was returned on the following day for a second attempt. The patient was again positioned described with her right arm abducted. Conscious sedation utilizing two mg midazolam hydrochloride and 100 ug fentanyl citrate was administered during a successful intubation procedure of the biliary tract. An 8F4 Percuflex (Medi-tech, Watertown, Mass.) biliary drain was placed.
Later that evening, the patient reported numbness in her arm and hand with an inability to clench her fist or lift her arm off the bed. A neurology consult was objected which reported findings consistent with a brachial plexus neuropathy. A motor and sensory grading of 3/5 for flexion and 3/5 for abduction at the shoulder combined with a limited 30 degree range of motion was documented. Sensory loss over the thumb and dorso-lateral aspect of the forearm was also present. Physical therapy was initiated and the patient regained complete motor and sensory function over the ensuing eight weeks.
Case 2: A 33 year old male was admitted to the department for percutaneous decompression of the biliary tract following a laparoscopic cholecystectomy injury. The patient was placed in a supine position with his right hand under his head and right arm in an abducted position. A right PBD was performed which demonstrated transection of the right hepatic duct with free spillage of contrast material into the peritoneal cavity. An 8Fr Percuflex (Medi-tech) biliary drain was placed. A total of six mg of midazolam hydrochloride and 200 ug of fentanyl citrate were utilized for conscious sedation. The patient reported nothing unusual during or immediately after the procedure. After the patient returned to his room, he noted that he was unable to move his right shoulder, arm, and hand. A neurology consult was obtained which reported findings consistent with a pan-brachial plexus neuropathy. Within 24 hours, he was markedly improved with grade 34/5 motor function in his forearm and hand; however, his deltoid function (shoulder shrug) remained graded at 01/5. Physical therapy was initiated and the patient regained complete motor and sensory function over the ensuing 26 days.
Case 3: A 13 year old female with a history of Tetrology of Fallot, pulmonary atresia and dextrocardia required evaluation for multiple episodes of pneumonia. A 2-dimensional echocardiogram demonstrated a right atrial pressure of 60 mm Hg and a right ventricular pressure of 70 mmHg secondary to a ventricular septal defect. A cardiac catheterization was desired to further evaluate the status of her pulmonary atresia for planning of potential balloon angioplasty and/or stent placement. One of our interventionalists (ACV) was present to assist if percutaneous intervention was necessary. The patient was placed in a supine position with both arms extended above her head. General anesthesia was utilized under the direction of the Pediatric Anesthesia department because of the age of the patient and the possible lengthy catheterization time. A diagnostic study with hemodynamics was performed but the right pulmonary artery system could not be effectively evaluated and thus no intervention was performed. The procedure time was four hours and 45 minutes. The patient was uneventfully recovered and discharged to home with no post procedure complaints reported or documented.
The following day, the patient was returned by her parents to the emergency room with complaints that her left arm felt like it was "twitching and asleep". A neurology consult was ordered. Fasciculations of the left deltoid, pectoralis, biceps, triceps, brachioradialis, and extensor policis muscle groups were noted. Motor strength was 5/5 in all muscle groups but sensation to pin-prick was decreased in the thumb and third and fourth digits. The neurologic findings were consistent with a brachial plexus injury focused on the C6-C7 nerve roots. Conservative care was recommended. The patient experienced a complete recovery over the ensuing two weeks.
The common factor in all three cases is the patient positioning utilized during these procedures. Traditionally, during a percutaneous transhepatic cholangiogram and biliary drainage proceedure, the patient lies supine with their ipsilateral (same side) arm hyperabducted, i.e. elbow displaced outwardly away from the side of the body, with the arm held above the patient's head to expose the flank, so that it does not interfere with catherization or imaging. It has become evident that positioning the arm in this manner stresses the nerves which travel from the neck to the arm.
More particularly, the mechanism for these three uncommon injuries is apparently a combined result of the stress placed on the brachial plexus during extension and/or abduction of the patient's arm at the shoulder (which was most likely compounded by the natural rotation of the head to the contralateral side), the procedure time, and the inability of the patient to report the occurrence of symptoms during the case secondary to the effects of conscious sedation. The patient positioning described for these procedures, namely extension and abduction of the arm at the shoulder and contralateral rotation of the head, is essentially identical to what is termed the `Adson's maneuver`. See, e.g., Adson et al., "Cervical ribs: a method of anterior approach for relief of symptoms by division of the scalenius anticus," Ann Surg 1927; 85:839. This diagnostic test is commonly used in the evaluation of the individuals with suspected thoracic outlet syndrome. This maneuver is designed to hyperaccentuate compression of the neurovascular bundle as it passes through the costoclavicular space. Two other narrow anatomic regions of the thoracic outlet, the interscalene triangle and subcoracoid space, may also be affected. Longley et al. "Color Doppler ultrasound of thoracic inlet syndrome." Semin Intervent Radiol, 1990; 7:230-235.
Although the positive predictive value of Adson's maneuver is variable, cadaveric studies have demonstrated that similar positional maneuvers can causes strain and elongation of the C5-T1 nerve roots. Selvaratnam et al. "Differential strain produced by the brachial plexus tension test on the C5 to T1 nerve roots." Proceedings of the 6.sup.th Biennial Conference of Manipulative Therapists Association of Australia, 1989. A number of anatomic structures including cervical ribs, anomalous first ribs, fibrous bands, and hypertrophied muscles can contribute to the localized trauma and are associated with compression of the neurovascular bundle. Pang et al. "Thoracic outlet syndrome." Neurosurgery 1988; 22:105-121; Pollak, "Thoracic outlet syndrome: diagnosis and treatment." Mount Kisco, N.Y.: Futura, 1986. In 95% of cases of thoracic outlet syndrome, neurologic rather than vascular compromise is responsible for patient presentation, thus indicating the relative vulnerability of the brachial plexus in comparison to the subclavian artery and vein. These three cases would indicate that under the right combination of circumstances, even individuals without a history of thoracic outlet syndrome can experience a significant brachial plexus injury during a prolonged Adson's maneuver.
In summary, brachial plexus injuries can occur during percutaneous procedures if the patient's (ipsilateral) arm is hyperabducted to expose the flank. The risk of injury is most likely increased with lengthy procedure times, but the rare occurrence of this complication does not allow for speculation on safe time limits for this patient position. The use of deep conscious sedation during many procedures such as PBD and vascular intervention, through typically utilized with the patient's best interest in mind with respect to pain control, can also contribute to the risk of injury if patients are unable to respond to the ongoing brachial plexus trauma which can occur during the procedure. The third case clearly indicates the patients under general anesthesia are also at risk if they are positioned with their arms extended and/or abducted for improved access to peripheral intravenous lines.
This complication has grave significance, and there is a real potential for its occurrence during any interventional procedure in which the upper extremity is abducted away from the operative field.
Accordingly, it is an object of the present invention to provide a device that supports the ipsilateral, i.e., same side, arm during a surgical or imaging procedure in a manner that reduces the stress on the nerves and positions the arm in a more natural position for patient comfort, without interfering with the surgical or imaging procedure. It is further object of the invention to provide an arm positioning device that is of simple construction that may be provided as an accessory to provide a simple solution for avoidance of this iatrogenic injury.
The foregoing objects have been realized by providing a unique arm board having a `well` for receiving the patient's forearm. The arm board places the patient's arm in a more neutral position, with the forearm just below the height of the table, so as not to overlap with the standard right mid-axillary line approach to the liver during PBD. For standard angiographic procedures, the patient's arm and hand are again below table top level, as opposed to adjacent to the body. Having the patient's arm positioned as such, the risk of a brachial plexus injury is eliminated. Moreover, the arm board is compatible with the necessary physician and C-arm positioning commonly utilized during a right PBD, other nonvascular procedures requiring similar patient positioning, and angiography.